Wireless communication devices such as cellular telephones, tablets, and laptops can support multi-cellular access technologies, peer-to-peer access technologies, personal area network access technologies, and location receiver access technologies, which can often operate concurrently. Wireless communication devices can be required to communicate at a variety of frequencies, and in some instances are subjected to a variety of physical and functional use conditions.
Multiple-Input Multiple-Output (MIMO) communication systems are being utilized due in part to their ability to increase channel capacity, and to often provide reliability in communication services. Channel capacity can be approximated using the Shannon-Hartley theorem, which states that channel capacity is a proportional function of signal-to-noise ratio (SNR) and bandwidth. Increasing the bandwidth of a signal in order to increase data rate can introduce multipath fading. MIMO systems can take advantage of multi-path fading by using a combination of antennas allowing the signals to propagate along different paths from transmitting antennas to receiving antennas. However, when multiple antennas are placed very close to each other, mutual coupling can have an adverse impact on the radiated signal.